It is provided a wind turbine and methods of operating a wind turbine as described herein.

Systems and methods for controlling operation of a power converter based on grid conditions are provided. In particular, a first gating voltage can be applied to a switching element of a power converter associated with a wind-driven power generation system. The first gating voltage can be greater than a threshold voltage for the switching element. A grid event associated with an electrical grid coupled to the power generation system can be detected. A second gating voltage can be applied to the gate of the switching element during the detected grid event. The second gating voltage can be greater than the first gating voltage.

A method which is suitable for a system having a frequency converter and a generator, both of which are connected to a power grid, includes obtaining sub-synchronous components of the grid voltage and determining damping current set points according to the sub-synchronous components to compensate for sub-synchronous resonances of the grid. Damping current set points are determined by receiving the sub-synchronous components of the grid voltage and returning damping current set points as outputs. A variable damping gain is adjusted according to the sub-synchronous frequency of the grid, such that the required compensation level can be adapted to the frequency converter for damping sub-synchronous resonance of the grid.

A method for providing grid-forming control of a double-fed wind turbine generator connected to an electrical grid includes receiving at least one control signal associated with a desired total power output or a total current output of the double-fed wind turbine generator. The method also includes determining a contribution of at least one of power or current from the line-side converter to the desired total power output or to the total current output of the double-fed wind turbine generator, respectively. The method also includes determining a control command for a stator of the double-fed wind turbine generator based on the contribution of at least one of the power or the current from the line-side converter and the at least one control signal. Further, the method includes using the control command to regulate at least one of power or current in the stator of the double-fed wind-turbine generator.

System and methods for optimizing operation of a wind turbine are disclosed. In one aspect, the method also includes determining, via a converter controller of a power converter, a tap position of a tap changer configured between the power grid and a primary winding of a transformer. Another step includes calculating, via the converter controller, a primary voltage of the primary winding as a function of the tap position. The method also includes implementing, via the converter controller, a control action if the primary voltage or a measured secondary voltage of a secondary winding of the transformer is outside of a predetermined voltage range.

A drive system has: a three-phase motor, having: a shaft, a first three-phase winding set, having: a three-phase stator winding for connection to a three-phase alternating voltage network and a three-phase rotor winding, which is coupled to the shaft in a mechanical, rotationally fixed manner, a second three-phase winding set, having: a three-phase stator winding for connection to the three-phase alternating voltage network in such a manner that rotary field is produced that runs in the opposite direction to a rotary field that is produced by the stator winding of the first winding set.

A method for providing grid-forming control of an inverter-based resource includes receiving, via a controller, a power reference signal. The method also includes determining a dynamic power change limit. Further, the method includes determining, via the controller, an upper power boundary and a lower power boundary for grid-induced power deviations from a desired power operating point based on the power reference signal. Moreover, the method includes determining, via the controller, limits for an inertial power regulator reference based, at least in part, on the upper and lower power boundaries and the dynamic power change limit. In addition, the method includes applying, via the controller, the limits to the inertial power regulator reference in an inertial power regulator of the inverter-based resource.

A method for damping sub-synchronous control interactions (SSCI) in a grid-forming inverter-based resource connected to an electrical grid includes receiving, via a controller, a current feedback signal in a synchronous reference frame. The method also includes rotating, via the controller, the current feedback signal to a new reference frame associated with a sub-synchronous frequency range. Further, the method includes determining, via the controller, a sub-synchronous component of the current feedback signal. Moreover, the method includes rotating, via the controller, the sub-synchronous component of the current feedback signal back to the synchronous reference frame. In addition, the method includes determining, via the controller, a voltage command associated with sub-synchronous damping for the inverter-based resource as a function of the sub-synchronous component and a virtual resistance setting. Thus, the method includes controlling, via the controller, the inverter-based resource, based at least in part, on the voltage command associated with the sub-synchronous damping.

A method for operating a wind turbine power system connected to an electrical grid includes collecting data relating to one or more parameters of one or more electrical components of the wind turbine power system. The method may also include performing a statistical analysis of the data relating to one or more parameters of the one or more electrical components. Further, the method includes predicting future behavior of the electrical component(s) based on the statistical analysis. Moreover, the method includes determining set points for the electrical component(s) using the predicted future behavior. In addition, the method includes operating the wind turbine power system at the determined set points for the electrical component(s) so as to optimize at least one characteristic of the electrical component(s).

A method for operating an asynchronous doubly-fed wind turbine generator connected to a power grid in a grid-forming mode to emulate a virtual synchronous machine. The doubly-fed wind turbine generator includes a line-side converter coupled to a rotor-side converter via a direct current (DC) link. The method includes receiving, via a controller, at least one reference command from an external controller. The method also includes controlling rotor flux of the doubly-fed wind turbine generator using the at least one reference command. Further, the method includes providing power droop control for the doubly-fed wind turbine generator through at least one of rotor-side reference frame rotation and d-axis flux control.